Power Losses and Thermal Modeling of A Voltage Source Inverter

This thesis presents thermal and power loss models of a three phase IGBT voltage source inverter used in the design of the 625KW fuel cell and reformer demonstration which is a top priority for the Office of Naval Research. The ability to generate thermal simulations of systems and to accurately predict a system’s response becomes essential in order to reduce the cost of design and production, increase reliability, quantify the accuracy of the estimated thermal impedance of an IGBT module, predict the maximum switching frequency without violating thermal limits, predict the time to shutdown on a loss of coolant casualty, and quantify the characteristics of the heat-sink needed to dissipate the heat under worst case conditions. In order to accomplish this, power loss and thermal models were created and simulated to represent a three phase IGBT voltage source inverter in the lab. The simulated power loss and thermal model data were compared against the experimental data of a three phase voltage source inverter set up in the Naval Postgraduate School power systems laboratory.